1. Field of the Invention
The present invention relates to a sheet storage device, which is equipped with a plurality of sheet storage portions holding sheets in a substantially vertical direction, and an image forming apparatus equipped with the sheet storage device.
2. Description of the Related Art
In the prior art, as a sheet storage device provided in this type of image forming apparatus, there has been known a bin movable type sorter movably equipped with a plurality of bin trays (stack trays) capable of storing sheets discharged after image formation thereon (see, Japanese Patent Laid-Open No. 8-048458). In addition to this, there has been known a bin fixed type sorter in which a sheet conveying portion moves relative to each bin tray of a plurality of fixed bin trays to selectively convey a sheet into the bin tray.
The sorter (sheet storage device) disclosed in the Japanese Patent Laid-Open No. 8-048458 is a so-called bin movable type sorter, and each of a plurality of bin trays stored in the vertical direction is moved up or down one by one by one rotation of a spiral cam provided on the both sides. A sheet formed with an image by an image forming apparatus body is conveyed to a sorting device through a discharge roller pair and selectively conveyed in a direction of a sort path or a non-sort path by a switching member (flapper) switched by rotation.
While a sheet passed through the non-sort path is discharged onto a non-sort tray, a sheet passed through the sort path is discharged by a discharge roller and placed on each bin tray lifting and lowering in synchronism with the discharge. The sheets stored on the bin tray are aligned by rotation of an alignment rod penetrating through a cut-out portion opened in each bin tray, and, according to need, staple processing is further applied to the sheets by an electric stapler. When a user takes out an output sheet, all the bin trays are simultaneously drawn out on the near side by the rotation of the alignment rod.
However, in order to sort sheets, the above conventional sheet storage device is configured so that the bin trays are stacked and arranged in the vertical direction, and the bin tray onto which a sheet is discharged is changed for each job of a discharged sheet. In the sort device, there is a height difference in a position of each bin tray, and visibility and taking-out property of sheets placed on lower bin trays are not particularly good. Since all the bin trays are drawn out on the near side when a sheet is taken out, the visibility of sheets placed on the bin trays other than the uppermost bin tray is not good.
The above conventional sheet storage device is disposed in a horizontal downstream direction (width direction) relative to a discharge portion of an image forming apparatus. Thus, the device size in the width direction of the entire system including the image forming apparatus and a sheet loading device is required to be further increased by the conveying direction length of the size of a sheet to be discharged with respect to a discharge portion of the image forming apparatus.
The present invention provides a sheet storage device, which can enhance a sheet taking-out property in taking out of a sheet from a stack tray and visibility of a sheet, and an image forming apparatus equipped with the sheet storage device.